Saturday, November 12, 2011

100% renewables, no hot air

Zero Carbon Australia's Matthew Wright has a response to a recent competing proposal for 100% renewable energy from UNSW's Mark Diessendorf - 100% renewables, no hot air.
The Zero Carbon Australia Stationary Energy project has paved the way for Australian researchers to contribute their best scenarios for transitioning to a 21st century renewable powered economy in a decade.

When we first set out on the momentous task to write the plan, recruiting dozens of engineers, physicists and scientists, we really hoped that we would create a competition around the goal on who could write the best scenarios for transition. We wanted to see reports like ours being written by state and federal governments, public and private research institutions and universities. We congratulate UNSW for being the first institution to take up the challenge.

As the community partner in the ZCA project, Beyond Zero Emissions welcomes the UNSW’s contribution with its soon to be released scenario for taking the economy to 100 per cent renewable energy.

Before we can discuss the merits of their proposal, we need to consider the two schools of thought on how to achieve a completely decarbonised economy: those who think we should have a fossil fuel powered "transition;" and those who think that transition using fossil fuel “lite” technologies – namely fossil gas – is a diversion, not a shortcut. Beyond Zero Emissions fit into the latter category while the UNSW fit somewhere in between.

Based on what is known about the UNSW plan, the research recommends building gas peaker plants to generate 14 per cent of Australia’s electricity needs. These plants would run on fossil gas – which would include petroleum gas and coal seam gas – and switch to gasified biomass at an unspecified point in the future.

We believe that it is simplistic and naïve to believe that fossil gas feedstock will be replaced with biomass feedstock, and think that future scenarios from universities and environmental organisations will send a green light to oil and gas companies Origin Energy, AGL, Santos, etc, to proceed with their massive expansion of coal seam gas in the food producing areas and forests of NSW and QLD; not to mention their intentions for Tasmania, Victoria, West Australia and their shale gas dreams in SA.

Even if the switch to biomass was contemplated on the studies' proposed scale, BZE’s research team had already looked seriously into biomass burning for the specific task of addressing reduced solar and wind resources in the winter. After diligent analysis, it was decided that a combination of overcapacity and biomass co-firing would be the best, least environmentally damaging and cheapest way to meet the more challenging winter demand.

The UNSW team, by their own admission, hasn’t done the economics on their transition plan, and so Beyond Zero Emissions can’t actually comment on the costs directly. What we do know is that our researchers ruled out the gasification of biomass due to the lack of demonstrated commercial-scale projects, the lack of project pipeline and known cost curves, and the fact that storage wasn’t demonstrated on any scale.

The UNSW use of biogas or biomass gasification was investigated, however research found that no technology existed on the scale needed and the costs quoted were as much as 10 times the cost of transporting biomass pellets. Palletisation as chosen by the Zero Carbon Australia team is a very well known process, with a significant scale industry operating in Europe and the US.

The challenge for the UNSW team is to either size their gas production for the maximum peak demand of their turbines, which I would expect would be in the order of 20-50GW of capacity, or to add storage for their gasified biomass, which is a costly option. The UNSW proposals might combust hydrogen and carbon monoxide directly, or alternatively reform the gasified biomass into methane, but both these options would prove to be very expensive. We are confident that our plan will be cheaper than the UNSW plan if they decide to stick to their choice of gasified biomass.

Gas generation is the most notable difference between the Zero Carbon Australia plan and the UNSW scenario but it’s not the only one.

The ZCA included a significant energy efficiency program, the most ambitious one proposed to date, which shows how we can deliver half the end use energy we currently deliver. How we do that is being comprehensively detailed in the work of the Zero Carbon Australia Buildings plan, which will be published in February next year.

Then there’s our plan to link the main electricity grids in Australia: the Mount Isa mine grid in the north and the eastern seaboard grid with the West Australian grids. This proposed updating of infrastructure is on par with what’s happening in China, in South America, and serious plans to connect North Africa and the Middle East to Europe. Our plan to link eastern and Western Australia with HVDC, creating a national grid, is consistent with the recommendation of Siemens Australia. The cost of this technology has come down since we researched and produced our report.

In his article last month, UNSW's Mark Diesendorf questioned whether Australia has the available labour force to build the renewable energy system, even though it is adequately addressed in the ZCA plan. When the coal industry is set to triple in size, we hear a bit about capacity constraints, but nobody concludes it’s a showstopper. When the gas industry decides its going to build $100, $200 or even $400 billion worth of LNG trains, no one says that it can’t be done because of capacity constraints. Not only does the same logic apply to a rapid rollout of renewables, but workers are crying out for jobs in the renewable powered cleantech economy.

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